Reaching ages over 60 years, chimpanzees are one of the few animals that approach human longevity. While we've long viewed old age in humans as unique, a recent study shows that the difference between human and chimpanzee lifespans is smaller than previously thought (Wood et al., 2016).
Here in Kibale National Park, my research on the Ngogo chimpanzees focuses on old age and asks why they have such extended lifespans. Here are a few photos of these wizened warriors from this past week.
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Dexter (b. 1985). Old yet? Not quite. Dexter is 32, which would be old for many primates, but not chimps who stay in their prime until ~30. Still, Dexter might be exploring early retirement for he is known for taking frequent naps.
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Garrison (b. 1977). One of the highest ranking males in the West, 40 year old Garrison here is groomed by Buckner (b. 1999)
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Monk (b. 1972). The grizzled warrior, you can spot Monk's scar on his upper lip. Monk comes from a legacy family of high ranking chimpanzees. Pictured here groomed by younger male, Hicks (b. 1997). Check out his mom, Garbo, below.
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Garbo (b. 1956). A practical matriarch, at 61 Garbo is still a social butterfly. She travels and even patrols with her sons, including Monk.
How do you know how old they are?
Researchers began to follow these chimpanzees regularly only in 1995, so ages for individuals older than this are estimated using data like reproductive behavior and appearance. Check out the Wood et al. article below for info on age estimations.
What's the oldest chimpanzee at Ngogo?
That prize currently goes to Marelene (b. 1950) with a close second Harper (b. 1952).
Do females live longer than males?
Yes, females have a much older life expectancy than males. In the top 10 oldest individuals at Ngogo, there is only one male (Brownface b. 1966). Check out my earlier post on hunting for a photo of him.
Do females chimpanzees experience menopause?
Many wild female chimpanzees experience a short post-reproductive lifespan (perhaps about 1/4) , which means that they stop giving birth to young, or even being able to conceive. In a study that examined the fertility and mortality patterns across six wild populations, Emery Thompson et al. (2007) found that chimpanzee and human birth rates show similar patterns of decline beginning in the fourth decade. Menopause was once thought to be uniquely human, but this is now up for debate with evidence among chimpanzees and whales as well.
Emery Thompson, M., Jones, J. H., Pusey, A. E., Brewer-Marsden, S., Goodall, J., Marsden, D., … Wrangham, R. W. (2007). Aging and Fertility Patterns in Wild Chimpanzees Provide Insights into the Evolution of Menopause. Current Biology, 17(24), 2150–2156. http://doi.org/10.1016/j.cub.2007.11.033
Wood, B. M., Watts, D. P., Mitani, J. C., & Langergraber, K. E. (2016). Favorable ecological circumstances promote life expectancy in chimpanzees similar to that of human hunter-gatherers. Journal of Human Evolution, 105, 41–56. http://doi.org/10.1016/j.jhevol.2017.01.003
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This is really cool! Do the chimpanzee's that are older tend to act like they are retired (to use familiar terms)? You mentioned that Garbo still goes out and patrols, but is that common for a chimp that age? What cool research you are doing. Good luck and stay safe!
I think this is a good question because it's a focus of my research! It seems like some individuals behavior changes. Some old male chimpanzees become less social, travel in smaller parties, and participate less frequently in behaviors like territorial boundary patrols. Looks kind of like retirement. But with the females? It's less clear. Garbo is definitely exceptional for her gregariousness, however, since not all females patrol regularly at any age. Thanks @ekpickle
wow... stunning! I can't imagine what it must be like to be in the forest with them.
thanks for sharing and I am following for sure!
Thanks @fraenk! i hope to keep the posts coming to try and communicate what it's like day to day :) cheers
Amazing photograph of Garbo lounging subtlety in the background behind Monk! Hilarious. Incredible photography, brother. You're really great at capturing the character / individual mannerisms of each chimp you observe. Be safe out there. Can't wait for more :)
Resteemed.
Thanks! And all with this ol' D40 someone gave to me....
Nah, the photos are nothing compared to what some are able to capture here, but I am getting better at it. I just missed a great shot of a chimp dragging a duiker corpse across a river the other day. Gotta be ready out here.
Supporting you in your cause for chimpanzee research!
Thank you!
So great to get to know these chimps, I can see something of each personality in the photos, excellent post!
thanks @natureofbeing, that means a lot coming from you! Love your posts
great to hear, thanks so much! Keep posting, you have a lot to offer!
Great pictures and information! More, please...! Soon, I hope. Share stories of how you manage to locate chimps every day. How far do you have to go? Do they flee humans or cautiously watch the scientists? Are some more interested in humans than others? Do you think your presence changes their behavior? Do they watch you eat? (As you can see, I'm full of questions!) And, yes... Good luck out there!
thanks again @oldfangle. I hope to answer more of these questions upcoming posts about the day-to-day, but these are well habituated chimps that it's easy to observe. Here's a copy-paste of an earlier reply to a similar question
I'd love to read a piece by you on the art of napping - chimpanzee style. Where is best? Does that differ from nighttime sleeping places? What time of day? Are others around? Do they nap together? How long? Are they refreshed afterward? Do you ever nap in the field? (Be honest - I won't tell!)
Finding a Steemian like you is why I love Steemit. We have an in house Primatologist.
How long have you personally been following this group? A great interest of mine has been to follow the observations being made between Chimps, Bonobos and human evolutionary psycology.
I would love to get your take on this subject. What is your knowledge on Bonobos? I know you are studying chimps at the moment, but I'm just wondering if that has been a subject of interest to you as well.
Particularily violence with chimp societies. Have you ever observed violence within the group or towards other groups? I ask because of the General peacefulness within the Bonobo societies. I know that the violent ape hypothesis came from studies partly by Jane Goodal (please correct me if I am wrong). But some people have criticized certain studies they did because of the way they interfered with the environment of the studied groups. Where the reseaerchers were leaving Bananas in a certain location at certain times. The criticism is that the reason the researchers were criticized was because they had created a finite resource for the chimps and had introduced an element of scarcity into the group, generating much more violence. Often seen in humans when there is scarcity present in the environment. Of coarse correct me on any of what I just said. I may as well be talking out of my ass, but that is the extent on my knowledge regarding it.
I'm interested because I find it curious how people will justify human behavior, particularily greedy, violent, egoitistical behavior within our species, because of the Violent primate hypothesis. But they fail to mention the correlation of humans to Bonobos, and there general peaceful society. Considering that Human are equidistant genetically to Bonobos as they are Chimps. Again correct me if I am wrong.
I think Bonobos are an interesting animal because of the lack of violence observed. But do you think Chimps are as violent as we are led to believe? What kind of violence have you seen in your study? And what caused it?
Again sorry if I botched any of that. This is a topic of great interest of mine. Evolutionary psycology.
Keep up the good work!